The vehicle body has the vehicle identification number that is a unique to the vehicle engraved in the vehicle body. In general, the vehicle identification number has a series of symbols with a combination of alphabet letters and numerals. In general, a vision system is used for determining whether the vehicle identification number engraved in the vehicle body is correct or not.
A related art vehicle identification number system is provided with a lighting for directing a light to an engraved surface, and a camera for taking a photograph of the light reflected at the engraved surface to recognize the vehicle identification number engraved in the vehicle body.
However, the related art vehicle identification number system has a problem in that, if the camera takes an image of the vehicle identification number having a contaminated vehicle body surface, a vehicle identification number recognition error takes place in a step of converting the image into a binary data.
Another problem with the aforementioned system is that irregular reflection at a portion of the vehicle identification number on the engraved surface caused by variation of the position of the lighting results in a failure to correctly identify the vehicle identification number from the image the camera had taken.
Moreover, there has been another problem in that a light quantity reflected at the engraved surface varied with the position of the lighting directed to the vehicle body requires many standard patterns of symbols for recognition of the same symbol.
Moreover, another problem with the related art vehicle identification number system is that it cannot perceive an engraved depth of the vehicle identification number because the camera takes a two-dimensional image.
The above information disclosed in this Background section is only for enhancement of understanding of the background of the disclosure and therefore it may contain information that does not form the prior art that is already known in this country to a person of ordinary skill in the art.